Method of wafer recycling

A method, comprising:

• depositing hafnium oxide (HfO2) on a first batch of semiconductor wafers, the first batch of semiconductor wafers including a first production wafer, a first particle control wafer, and a dummy wafer;
• removing the deposited hafnium oxide from the dummy wafer by etching the dummy wafer with a hydrofluoric acid solution;
• and
• polishing the dummy wafer by chemical-mechanical planarization.

A method, comprising:

• depositing hafnium oxide (HfO2) on a first batch of semiconductor wafers, the first batch of semiconductor wafers including a first plurality of production wafers, a first particle control wafer, and a dummy wafer;
• measuring a thickness of a first hafnium oxide layer on the dummy wafer;
• determining whether the measured thickness of the first hafnium oxide layer exceeds a threshold thickness;
• in response to determining that the measured thickness of the first hafnium oxide layer is less than the threshold thickness, reusing the dummy wafer by depositing hafnium oxide on a second batch of semiconductor wafers, the second batch of semiconductor wafers including a second plurality of production wafers, a second particle control wafer, and the dummy wafer;
• measuring a thickness of a second hafnium oxide layer on the dummy wafer, the thickness of the second hafnium oxide layer including the thickness of the first hafnium oxide layer;
• determining whether the measured thickness of the second hafnium oxide layer exceeds the threshold thickness;
• in response to determining that the measured thickness of the second hafnium oxide layer exceeds the threshold thickness, removing the second hafnium oxide layer from the dummy wafer by etching the dummy wafer with a hydrofluoric acid solution;
• and
• polishing the dummy wafer by chemical-mechanical planarization.